Influence of mechanical ventilation and loading modifications on left ventricular global longitudinal strain in patients undergoing general anesthesia: a pilot study
Bibliographic record
Abstract
BACKGROUND: The modifications of left ventricular systolic function assessed with global longitudinal strain (GLS) after general anesthesia and invasive mechanical ventilation are poorly described. METHODS: This was a single-center observational study. ASA I-II patients undergoing routine surgical procedures requiring anesthesia with invasive mechanical ventilation had serial trans-thoracic speckle-tracking echocardiography: at baseline, five minutes after anesthesia and invasive mechanical ventilation, one minute after passive leg raising and after extubation. The primary objective was to evaluate the modification of left ventricular systolic function, assessed with GLS, under anesthesia and mechanical ventilation. Secondary objectives were to evaluate the alterations of GLS after pre-load modifications with passive leg raising and after extubation. RESULTS: From November 2016 to July 2017, 27 patients were included. Baseline left ventricular ejection fraction (LVEF: 60% [56-63]) and GLS (-20.6% [-23.2/-19.2]) were within normal ranges. After anesthesia, LVEF was not altered but GLS showed a significant decrease (-18.2% [-20.4/-17.1], P<0.05). After passive leg raising, GLS was significantly impaired compared with baseline (-17.6% [-19.7/-15], P<0.05) and seven (26%) patients presented systolic function impairment (GLS >-16%). GLS was similar to baseline after extubation (-21.7% [-23.1/-19.5], P>0.05). CONCLUSIONS: Systolic function assessed with GLS is impaired after general anesthesia and invasive mechanical ventilation in patients without cardiovascular co-morbidities but remains within normal range.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".